7. Anthozoa (incl. Hydrocorallia). A. Zoantharia. 27 



the 4th couple of tentacles and before that of the 5th couple. In bourn, and 

 brack, the median tentacle develops practically synchronously with the members 

 of the 3d couple. The ventral couple of mesenteries in all Cerianthese is 

 associated with the single siphonoglyph ; these mesenteries are short, sterile 

 and without filaments. The members of the succeeding couple, in most known 

 species, extend to the aboral extremity, are fertile und have filaments. The 

 author names them telocnemes . They are the 4th (not the 2d) couple in 

 PachycerianthuSy in two species of the Siboga collection and in Cerianihus oligo- 

 podus. In A. alb. and sib. the most ventral acontia are present on the mesen- 

 teries of the 4th couple (counting from the mid-ventral line) and these would 

 probably become the telocnemes. This condition also occurs in the larval genera 

 Dactylactis and Ovactis. The author proposes to divide the acontiferous Ce- 

 riauthese, according as the telocnemes are the 2d or 4th couple, into 

 the families Cerianthidse and Arachnactidse (A., D., 0., P.). Probably A. brack. 

 and bourn, are larvae of Cerianthus. 



Pesch reduces the known species of Cirripathes to 3, namely, anguina, spi- 

 ralis and paucispina. The two former are more clearly defined by the aid of 

 the numerous well preserved specimens in the collection made by the Siboga, 

 pauc. is represented by one doubtful specimen; 6 n. sp. are described. The 

 characters relied upon are mainly those presented by the polyps, but the nature 

 of the axis and arrangement of the spines are also utilised. C. is not so sharply 

 circumscribed as Brook thought, the colony is not always unbranched, for 

 ntmphii (n.) shows, in places, small rounded prominences, sometimes grouped, 

 one of which is 5 mm. long (the colony is 4.5 m.); some specimens of ang. bear 

 branches (the longest of which is 15 mm. long, the whole colony is .5 m.), 

 which have the same kind of conical swollen apex as the colony itself. 

 C. ramosa (n.) is dichotomously branched in two places, but otherwise has the 

 characters of C. Through these 3 species the Indivisse are linked with the 

 Ramosa?. The distribution of the polyps round the axis in several irregular 

 rows and never in a single linear series*, by which character C. is said to 

 be distinguished from Stichopathes, is not constant, for in the upper part of 

 old colonies and throughout young ones of C. the polyps are in a single row. 

 The structure of the polyp is also not peculiar to C., for many of the cha- 

 racters are found in other branched genera. Canals are not invariably present 

 in the coenenchym. C. is a shallow water form; most of the specimens found 

 by the Siboga were taken in the Banda Sea. The anatomical part of the 

 memoir reviews the anatomy of the Antipatharia in general. The author has 

 made sections of the upper parts of the colonies of 8 species of C. with the axis 

 in situ, using hard paraffin (60). Tentacles. The ectoderm may contain nu- 

 merous nematocyst-batteries or not; the ectoderm has usually longitudinal, and 

 the endoderm circular, muscle fibres; sometimes the mesoglcea exhibits pro- 

 jections supporting the muscles; it contains, in some species, local accumu- 

 lations of oval or round (never stellate) connective tissue cells, which are but 

 sparsely distributed in other parts; numerous sections show in the mesogloea 

 delicate transverse fibres (sometimes swollen here and there), which connect 

 the bases of the ectoderm and endoderm layers; these fibres are often nume- 

 rous where the tentacle merges into the body wall. The body wall has a 

 similar structure to that of the tentacles, except that muscle fibres and nemato- 

 cysts are usually wanting; the latter are, however, often present on the oral 

 cone and gland cells are also more numerous there. Between the polyps the 

 body wall forms an inter-zooidal septum. There is no relation between the 

 thickness of the mesogloea and the length of the spines, as Roule supposed. 



